1. Field of the Invention
This invention relates to a liquid composition, a method of cleaning an ink-jet recording head, an ink-jet recording apparatus, an ink cartridge, and a method of regenerating an ink-jet recording head.
2. Related Background Art
Various ink-jet recording methods have been proposed, and among them, the ink-jet recording method described in Japanese Laid-Open Patent Application No. 54-51837 etc., the so-called bubble-jet recording method, utilizes thermal energy for ejecting ink as ink droplets. The features of this method are that a high density multi-nozzle system can be easily set up, it can provide high quality images at a high speed and at a very low cost, and it enables printing on plain paper having no special coating.
The recording method known as the bubble-jet recording method carries out recording as follows: a bubble is generated in the ink on the heater of the recording head by rapid heating of the heater, and by the action of the bubble inflating rapidly in volume, an ink droplet is ejected from a nozzle located at the top of the recording head and it flies and attaches to the recording paper for recording.
In the above bubble ink jet recording method, however, the heater in the recording head is repeatedly heated for ink ejection, and when a large amount of recording is carried out, the decomposition products of the ink (so-called xe2x80x9ckogaxe2x80x9d) will be deposited on the surface of the heater. Deposition of koga (so-called xe2x80x9ckogationxe2x80x9d) prevents efficient thermal energy transfer to the ink, which may lead to a decrease in the volume and flying speed of the ejected ink droplet in comparison with those at the beginning, or even in stoppage in ejection. Thus, reduction of the kogation on the heater has been sought and various ink formulations have been proposed to improve the life of the bubble-jet recording head. There have been proposed various methods; for example, methods to decrease the amount of impurities in the ink or dye, methods to modify the ink formulation, e.g., inks containing oxoanions (Japanese Laid-Open Patent Application No. 3-160070), bile acid salts (Japanese Laid-Open Patent Application No. 5-194888), and an amine compound of a specified formula (Japanese Laid-Open Patent Application No. 6-220386). However, kogation may occur and lead to poor ejection after a long use of the printer, for example, after a number of renewals of the ink container of a printer in which the ink container and the recording head are separated. Also, it is difficult to recover the used cartridges from the recording heads in a recycling plant.
Japanese Laid-Open Patent Application No. 9-39260 discloses a method to clean the heating head of an ink-jet recording apparatus with a liquid containing water and a surfactant, which liquid, the inventors of the present invention have found out, is not adequate to completely remove the koga deposited on the heater of the recording head.
On the other hand, the heater surfaces of newly produced ink-jet recording heads are often soiled through the various manufacturing processes, which leads to unstable ink ejection at the beginning of usage. To solve this problem, for example, Japanese Laid-Open Patent Application No. 2-78554 discloses to carry out an aging treatment for steady ink ejection. The aging treatment, however, may result in kogation on the heater surface, which reduces the ejection volume, and prevents full exhibition of the intrinsic performance of the head, even at the very beginning of usage. Considering the technical background and the present inventors"" study as above, as well as the increasing worldwide requirement for resource recycling, the inventors of the present invention have come to acknowledge a need of developing superior methods for removal of the deposit on the heater surface of the ink-jet recording head.
Accordingly, an object of the present invention is to solve the aforementioned problems, in particular, to provide a liquid composition, for use in an ink-jet recording head utilizing thermal energy, which is capable of cleaning/removing koga or soil deposited on the heater surface of an ink-jet recording head after long usage or during its manufacturing processes, and hence improving the life and ejection characteristics of the ink-jet recording head.
Another object of the present invention is to provide a method of cleaning an ink-jet recording head which enables the improvement in the life and ink ejection characteristics of the above ink-jet recording head by cleaning/removing koga or soil deposited thereon, in addition, an ink-jet recording apparatus utilizing the above liquid composition and containing means of performing the above cleaning method.
Further, another object of the present invention is to provide a cartridge which enables a more excellent cleaning of an ink-jet recording head as well as an efficient and easy regeneration of the ink-jet recording head.
Still another object of the present invention is to provide a method of regenerating an ink-jet recording head which enables the reuse of the ink-jet recording head having been used for ejecting ink-jet ink and having deposits on its heater surface as a new ink-jet recording head used for the ink-jet recording of high quality images.
According to one aspect of the present invention, there is provided a liquid composition which contains a detergent in an amount effective in cleaning a portion of an ink-jet recording head.
According to another aspect of the present invention, there is provided a liquid composition for use to remove deposit on a surface of a heater of an ink-jet recording head wherein the recording head is used for ejecting an ink containing a coloring material and the surface of the heater is a protective layer comprising a metal or metal oxide or both; where the liquid composition is capable of oxidizing and decomposing the deposit when thermal energy is applied to the heater having the deposit and being in contact with the liquid composition.
According to still another aspect of the present invention, there is provided a method of cleaning an ink-Jet recording head using the liquid composition which contains at least one detergent in an amount effective in cleaning a portion of the ink-jet recording head.
According to still another aspect of the present invention, there is provided an ink-jet recording apparatus, which comprises a liquid container containing a liquid composition which contains a detergent in an amount effective in cleaning an ink-jet recording head; an ink container containing an ink; valve means for selecting one of the liquid composition and the ink to supply it to an ink-jet recording head; and an ink-jet recording head.
According to still another aspect of the present invention, there is provided a cartridge for use in cleaning of an ink-jet recording head having a heater of which a surface is coated with a protective layer which comprises a metal or a metal oxide or both, the cartridge containing a liquid composition comprising a compound having an oxidizing ability; and the cartridge being in a configuration detachable from the recording head.
According to still another aspect of the present invention, there is provided a method of regenerating an ink-jet recording head for ejection of an ink containing a coloring material wherein the head has a heater of which a surface is coated with a protective layer which comprises a metal or a metal oxide or both; the method comprises a step of applying thermal energy to the heater being in contact with a liquid composition, wherein the liquid composition contains a compound having an oxidizing ability.